Product developments in these days have become complicated and the scales have become intensified, and there may be many cases in which a development of a single product may involve multiple designers. At the same time, since advancement of computer networks, notably the Internet, have allowed distribution of product development portions at remote locations, communications of the designers developing the same product have become infrequent.
When a single product is designed by multiple designers, the responsibilities of the designers and the boundaries of the responsibilities are defined in advance. However, often times, the definitions of the boundaries have to be changed because of a variety of factors. When the definitions of the boundaries are changed, a designer have to modify his design portion he is responsible while making reference to other portions modified by other designers.
For example, let's assume a case wherein a product having two parts, namely, an upper portion and a lower portion, is designed by two designers. During design of the upper portion, a portion of a feature in the upper portion requires to go beyond the boundary between the upper portion and the lower portion. In such a case, the designer responsible for the upper portion has to request the designer of the lower portion to change the design. In response to the request, the designer of the lower portion modifies the design of the lower portion while checking features of the upper portion.
In such a case, if a PDM (product data management) system is employed, the designer of the lower portion can easily obtains and makes reference to the latest feature data of the upper portion. However, the designer of the lower portion has difficulty in identifying modified portions and details of modifications from the obtained latest feature data. For assisting the user to identify the modifications, some CAD systems or PDM systems have a feature to extract modified parts in the feature data as a difference and present it to a user.
Hereinafter, three methods to present differences in design modifications of a designed product in conventional techniques will be described with reference to FIGS. 14A and 14B.
FIG. 14A is a diagram illustrating a designed product 100 before a design modification, and FIG. 14B is a diagram illustrating the designed product 100′ after the design modification. In this example, in the designed product 100′ after the design modification, features are modified such that a new element 101 has been added to the designed product 100 before the design modification while a key opening 102 in the designed product 100 before the design modification has been deleted. In addition, in the designed product 100′ after the design modification, the width of 6×4 key openings 103′ is increased as compared to the 6×4 key openings 103 in the designed product 100 before the design modification. Furthermore, an element 104 in the designed product 100 before the design modification has been displaced to an element (power button) 104′ in the designed product 100′ after the design modification. The rounded portions of the edges (chamfering) have also been modified between the designed products 100 and 100′ before and after the design modification.
(1) Presentation of Differences by Means of Superimposition of Features
In FIG. 15, the difference before and after the modification is presented on a display by superimposing the feature data before the modification (image of the product 100) and the feature data after the modification (product 100′). More specifically, on the display, the feature data before the modification and the feature data after the modification are drawn and displayed in the same position using different colors. For example, when the feature data before the modification is displayed in blue and the feature data after the modification is displayed in yellow, non-modified portions will be displayed in green because blue and yellow are superimposed. This can allow a designer before the display to visually distinguish between portions present only in the pre-modification design, portions present only in the post-modification design, and non-modified portions. Since the designer can see the feature data before the modification and the feature data after the modification on the same screen, the differences before and after the modification can be easily identified. However, if a modified portion is smaller or is located behind another shape, the designer may overlook the difference.
(2) Presentation of Differences by Means of List of Modified Parts
In FIG. 16, the difference before and after the modification is presented on a display by listing the details of the modified parts. When the designer selects an item on the list on the screen, the portion of the feature data corresponding to the selected item may be highlighted. However, the designer cannot intuitively identify which portions in the feature data has been modified from the list of the details of modifications displayed on the screen. Even when the corresponding portion is highlighted, the designer has to select an item to be highlighted on the list, and the designer may experience difficulty in obtaining the entire picture of the modification. In addition, since every detail of the modifications is enlisted, the list often become very lengthy, which may increase the risk of overlooking significant modifications.
(3) Presentation of Differences by Means of Highlighting
In FIG. 17, the difference before and after the modification is presented on a display by highlighting the modified portions in the feature data after the modification (image of the product 100′) by displaying the difference in red or displaying it brighter, for example. In such a case, the designer can easily identify the modified portions, this presentation provides no suggestions on modification details, the pre-modification design and how the design is modified. Accordingly, the designer has to make comparison between before and after modification. In addition, if many modified portions are present, the designer tends to overlook minute changes.
Meanwhile, for presenting differences of design modification, the following technique is known in which the number of differences to be displayed can be reduced. For example, a technique has been known in which part information of two diagrams, such as connection diagrams of circuit diagrams, are mapped into the semantic space and the differences are extracted, thereby highlighting the portions to which meaningful modifications are made. In addition, another technique is known which detects a modified portion in a level that can be regarded as an electronic document update by means of pre-processing for extracting an important portion and a value determination unit that decides whether the extracted difference is a significant difference.
As described above, a CAD system or a PDM system can display a difference of feature data, and the presentation of that difference is utilized by multiple designers in a collaborative design task. However, in a conventional system, it is difficult for a certain designer to identify difference information that the designer requires from multitude of differences. This may cause a problem in which the designer may overlook a different that required to be checked, which may cause a problem.
The reason why such a problem arises is that multitude of differences a presented indiscriminately. Although there may be multitude of modifications by other designers, not all of the modifications are required to be checked by a certain designer. Accordingly, a need exists to present only information about modified portions that are required to be reviewed among a large number of modifications, depending on the designer.
The problem in that a lot of differences are detected is similar to those discussed in Japanese Patent No. 3761156 and Japanese Laid-Open Patent Application No. 2004-86851, the techniques disclosed in Japanese Patent No. 3761156 and Japanese Laid-Open Patent Application No. 2004-86851 cannot be applied to feature data that the present application is directed to.
The reason why the techniques disclosed in Japanese Patent No. 3761156 and Japanese Laid-Open Patent Application No. 2004-86851 cannot be applied to feature data that the present application is directed to will be described.
Japanese Patent No. 3761156 is a technique for presentation of differences in an electric circuit. In this technique, connection points and connection likes of a part is classified and compared by focusing on the potentials, and the semantic difference of an electric circuit is highlighted. In contrast, since the present application is directed to a CAD system that generates three-dimensional features, there is no notion of potentials. Thus, the technique of Japanese Patent No. 3761156 cannot be applied to the present application.
Japanese Laid-Open Patent Application No. 2004-86851 is a technique for difference presentation of electronic documents, such as Web pages or text data. The technique displays only modifications of important portions in an electronic document, and the technique for identifying important portions in a frame of the HTML (Hyper Text Markup Language), and the technique that determines important portions by means of the amount of differences and natural language processing. More specifically, these techniques are based on comparison of text data, and cannot be applied to three-dimensional features to which the present application is directed.